Board dropping device



April 30, 1957 Filed Dec. 5, 1952 F. FAHRNI BOARD DROPPING DEVICE 4 Sheets-Sheet 1 I I2 7' i mvr/v ran .Fred Fa/rrn/ AT TORNE'Y April 30, 1957 Filed Dec. 5, 1952 F. FAHRNI 2,790,562

BOARD DROPPING DEVICE 4 Shets-Sheet 2 A T TOR/V5 Y April 30, 1957 FAHRNl 2,790,562

BOARD DROPPING DEVICE Filed Dec. 5, 1952 4 Sheets-Sheet 3 MM I E P t .11; I 20 3/ 30 I ,9 :5 27 IHM'M m l W 0 3m} 7&8; m I: H'IIIIH V a 3/ 30 I7 I I I INVENTOI? Fred Fan/771' A TTORNE) April 30, 1957 F, FAHRNI 2,790,562

BOARD DROPPING DEVICE Filed Dec. 5, 1952 4 Sheets-Sheet 4 INVEN TOR. Fred Fem/m United States Patent BOARD DROPPING DEVICE Fred Fahrni, Zurich, Switzerland Application December'S, 1952, Serial No. 324,387 Claims priority, application Switzerland March 5, 1952 22 Claims. (Cl. 214-6) The present invention relates to a process and apparatus for stacking sheets, particularly sheets comprising wood particles and binders which have been pressed in a multiple press.

It is usual in the art to employ a multiple press in order to allow an economical manufacture of so-called synthetic wood sheets which, however, in addition to binder comprise actual wood particles such as shavings, chips, fibers and the like. Such multiple presses permit the simultaneous pressing of a larger number of sheets. In the press, there are alternately arranged one above the other a heating plate, a transporting plate and a prepressed sheet comprising wood particles and binders or a loose mixture thereof. After the pressing operation has been finished, it is usual to transport the transporting plates with the sheets thereon still hot to a multiple layer unloading frame and then to free the transporting plates individually one after another of the sheets arranged on them. The sheets can then be piled up to form a stack and be transported into a separate room for cooling in which they may remain without occupying much space for the duration of the cooling process lasting a few days.

With this procedure it is unavoidable that the sheets which are removed from the unloading frame later than others remain exposed at one surface thereof for a longer period of time on the transporting plates until they too are piled up or put aside for cooling, Accordingly, there may be an appreciable'lapse of time between the moment the unloading of the transporting plates is begun and the moment the last plate is finally unloaded. The thus originating time periods may be from 10 to 30 minutes depending upon the material and thickness of which the sheets are comprised, as Well as upon the number of plates originally accommodated in the multiple layer unloading frame.

It has been ascertained by tests that the exposure of the hot and uncovered sheets on the transporting plates leads to permanent stresses in the interior of the plates. The heat radiation from the exposed and unexposed surfaces of the sheets is, of course, not symmetrical with respect to the median plane of the sheets so that one side thereof cools and the curing thereof progresses further than in the case of the other side thereof. Furthermore, unsymmetrical humidities often occur because of the exposure of the sheets which frequently have a temperature exceeding 100 C. The intense heat radiation of the sheet has the effect of heating the adjacent ambient air and lowering the relative humidity thereof. In consequence thereof, the air, which moves by convection into contact with the exposed upper side of each of the sheets still containing up to 10% moisture, eagerly absorbs moisture. However, the lower side of each of the sheets maintains the moisture thereof since the latter is prevented from escaping by the particular transporting plate associated therewith.

It is an important object of the present invention to avoid the drawbacks described hereinabove. The invenmy inventive concept.

2,790,562 Patented Apr. 30, 1957 tion relates to a process for piling sheets pressed in a multiple press and particularly sheets comprising wood particles and binders. This process is characterized in that after the pressing operation, the sheeets are pushed into a frame so that the sheets are arranged one above the other without mutual contact, with each sheet being held along at least two edges arranged opposite to each other. Thereafter, all the sheets are simultaneously released so that they freely drop one on top of the other and thus form a stack.

Furthermore, the present invention relates also to an apparatus for carrying out this process. The novelty of this apparatus resides in the mentioned frame being provided with holding members for engagement by the edges of the sheets. In addition, releasing means are provided for cooperating with the holding members by which all the holding members can be moved simultaneously so that the sheets supported by the same may no longer be held and so drop freely. Preferably, at least two holding members are provided for the support of any sheet and are arranged at the same level.

Of course, the present invention is not limited to the piling up of sheets which are still hot. In certain cases it is advantageous to pile up sheets, which have been more or less cooled in a suitable way, in a stack within a short time.

Advantageously, the frame for the formation of the stacks is assembled with a multiple layer unloading frame of the press. It is best to arrange the press so that it is not in line with the two frames. If the press and the frame for forming the stacks are lined up so as to face two adjoining sides of the multiple layer unloading frame, favorable possibilities result. Specifically, the elements necessary for carrying out the operations of unloading the press and the elements necessary for separating the pressed sheets from the transporting plates in the unloading frame then do not interfere with one another.

Preferably, all the transporting plates with their respective pressed sheets thereon, while still hot, are removed simultaneously from the multiple press and into the multiple layer unloading frame. Then, again simultaneously, all the pressed sheets, while still hot, are pushed from their respective transporting plates (now held in the unloading frame) and into the stacking frame. Furthermore, the release of the sheets in the stacking frame is preferably carried out without loss of time and.

the uppermost plate covered. In this way, stresses cannot occur during the cooling operation, since with regard to none of the plates of the stack may an unsym metrical heat radiation or a unilateral transfer of moisture to the ambient air take place.

A simple solution for the transporting of the formed stack of pressed sheets consists in providing that before the sheets are dropped, a low transporting carriage having a plane table, is pushed underneath the stacking frame for receiving the stack. After the releasing of the sheets the entire stack can be transported without unloading.

With the foregoing and other objects in view as will appear from a reading of the following specification and claims, the invention resides in the novel arrangement and combination of parts and in the details of construction and process of manufacture hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention may be made within the scope of What is claimed Without departing from the spirit of the invention. It Will be further understood that the present invention is susceptible of embodiment in many and various forms, one of which is illustrated in the accompanying drawings, and that the structural details and particular steps of the method herein set forth may be varied to suit particularpurposes and still remain within other as indicated in Fig. 2.

In the following, the carrying .out of the process according to the present invention and an embodiment of the device required therefor-are described with reference to the drawings.

Fig. 1 shows diagrammatically a plan view of the arrangement of the press, the unloading frame and the stacking frame, the press being shown in a horizontal section;

Fig. 2 shows a detail in vertical section of a device known per se for pulling the transporting plates with the moment of the pushing of the sheets into the stacking frame;

Fig. 3a shows a horizontal section of one portion of the board supporting part of the carriage mounted on the stacking frame shown in Fig. 3, the section being indicated by line HIa-IIIa;

Fig. 4 shows the stacking frame after the sheets have been released and dropped, the stack of sheets formed thereby resting on the plane table of a transport carriage pushed underneath the frame; and

Fig. 5 relates to a side view detail of the device for pushing the sheets out of the unloading frame and into the stacking frame.

Fig. 6 is a skeletonized version of the apparatus shown in Fig. 3.

In Fig. 1 the reference numeral 3 indicates a multiple hot press known per se in the art. The device for charging the press 3 is not shown here, because this part has no connection with the invention and thus would not facilitate the understanding thereof. The particular press 3 illustrated contains twelve layers. Thus, twelve sheets can be pressed in one pressing operation. Of course, a press may be provided that has either a greater or lesser number than the twelve layers herein shown by way of example only. Since the press is shown in section in the diagrammatic view of Fig. l, the transporting plate 2a can be seen together with a pressed sheet In lying on the transporting plate 2a.

To the right of the press, as viewed in Fig. l, the unloading frame 6 is arranged; The transporting plates, when within the emptying frame 6, are denoted by 2b and the sheets thereon by 1b. The partial view in Fig. 2 illustrates a known arrangement for unloading the press. In the press there are arranged alternately heating plates 4, transporting plates 2a and sheets 1a one above an- The unloading frame best seen in Fig. 5 is provided with twelvetables 7 or any other member to correspond with the numberof layers in the press. Each table has associated therewith a pulling rod 8. The rods 8 are provided at the ends thereof which face the press 3with pawl arms 9, respectively, which are pivotable on said rods 8 about axes 11 mounted on said rods and are pressed downwardly in a counterclockwise direction as viewed in Fig. 2 by means of leaf springs 10, respectively mounted on'rods 8.

The ends of the pawl arms 9 remote from the ends carrying detent surfaces 9', respectively, provide swinging arms 13 each of which pivot as a rigid unit with its respective pawl arm 9 about the axis 11. The counterclockwise rotation of each swinging arm 3 about its axis is limited by an adjusting screw 14 mounted on each of the rods 8. Thus the limiting of counterclockwise rotation of the end of pawl arm 9 carrying the detent surface 97 by means of the leaf spring 10 is in the same manner. It will be apparent from inspection o'f'Fig. 2 that tightening of screw 14 causes, as a unit, a slight clockwise rotation of the combined pawl arm 9 and swinging arm 13 about axis 11. Since these combined arms 9 and 13 have a roller 12; secured'to one end thereof, which roller reposes on table 7, any downward movement plates 2a are used again.

of swinging arm 13 (or corresponding upward m ement of pawl arm 9) will force rod 8 and axis 11 which it carries, in an upward direction, and vice versa. It follows that the beveled end 7 of table 7 causes lowering of the entire pawl and rod assembly when roller 12 reaches such end. In this manner, detent surface 9' is lowered into the hole in the transporting plate 2a.

After the pressing operation has been finished, the press is opened, i. e., the heating plates 4 are separated from one another to permit removal of the transporting plates 2:; and pressed sheets 1n. Then, the twelve rods 8 are simultaneously shifted to the left by a drive (not shown) until the catches 'of the pawls 9 fall into the slots of the transporting plates 2a when rollers 12 reach bevels 7 as described previously. During the withdrawal of the rods 3 the transporting plates are taken along with the same and pulled togetherwith the hotsheets 1a carried by the same so as to rest on the tables 7. Before the end of the withdrawing motion ofthe rods 8, the pawls 9 are lifted and disengaged from the slots of the transporting plates 2a. This may be accomplished by having each supporting roller 12 come between a guide 171 and a second beveled end 7" on the right hand end of table 7 as seen in Fig. 2a. Stationary guide means 8 in which rod 8 rides functions as a support therefor to prevent vertical displacement thereof when it is in the position shown in Fig. 20. It will be apparent that the effectiveness of guide 8 upon vertical displacement of rod 8 will be diminished when a longer length thereof protrudes beyond the guide 8' as is the case when the rod is in the position shown in Fig. 2. As a result, when the parts assume the position shown in Fig. 2, the whole assembly including rod 8 is permitted to lower. On the other hand, when the rod 8 reaches the position shown in Fig. 2a, arm 13 is caused to rotate clockwise about pivot 11 on rod 8 so that pawl end 9 does likewise against the biasing action of leaf spring 10 with the result that detent 9' is lifted out of engagement with its respective transporting plate 2a. After the removal of the sheets as described more in detail hereinafter, the transporting However, this process of unloading the press is not novel.

In order to remove the sheets In from the unloading frame 6 and to separate the sheets In from the transporting plates 2a, two push rods 17 (Figs. 1 and 5) are provided for each stage of the unloading frame 6 and at the level thereof. Each push rod 17 is provided at one end thereof with a shoe member 19 consisting of a U- iron and a roller 18. The push rods 17 run between rollers 25 which are comprised of synthetic resin and are freely rotatable on spindles arranged on a vertical bar 26. At the rearward end thereofeach push rod 17 penetrates an angle-iron girder 27 to which it is fastened for movement therewith by means'of nuts 21 and 22' screwed on the thread 20 of the push rod 17. The driving means causing the uniform lateral shifting of the girder 27 and with it all the push rods 17 in the axial direction" are not shown in the drawing. 28' and 29 are parts of the unloading frame and the angle members 30 are the horizontally arranged supports carrying freely rotatable rollers 31 which rotate when the sheetslb slide on top of the same when the said sheets are pushed out by rods 17.

A frame 35 for forming the stack of plates is positioned adjacent the unloading frame 6 as shown in Fig.

1. Posts 36 support two parallel I-beams 37, the ends of which are connected. L l-shaped members 38 to shaped' members .serve .to reinforce vertical flat iron sections'i46. 'Analogous flat iron'sections 47 are arranged attlie sides of the posts 36.

. Between each pair of fiat iron sections 46 and 47 and at right angles thereto are arranged supporting bars 50 and 51. The supporting bars are provided in two parallel rows comprising twelve bars each. The supporting bars 50 and 51 are provided at the ends thereof with spindles 150 and 151 fixedly connected thereto and pivoting, respectively, in borings in the flat sections 46 and 47. The spindles 150 of the left hand row of supporting bars 50 are provided, respectively, with small swinging arms 54 fixedly connected thereto and the spindles 151 of the right hand row of bars 51 are welded, respectively, to swinging arms 55. All swinging arms 54 are pivotally linked to a rod 52 by means of spindles 152 fixedly attached to arms 54 and rotatable in borings in rod 52. If the rod 52 is lifted or lowered, the supporting bars 54 of the left hand row are rotated. A pawl 60, rotatable about a pivot 57 on the plate 44 as best seen in Fig. 4, and held in locked upright position by means of a roller 71 of a two-armed lever 70 as shown in Fig. 3 is linked at 56 to an intermediate member 68 which in turn is linked to rod 52. In order to rotate the supporting bars of, the right hand row, a rod 53, an intermediate member 69 linked thereto, a pawl 61 rotatable about a pivot 59 arranged on the I-beam 37 and connected at 58 with the intermediate member 69 are provided. The pawl 61 can be released by means of a roller 75 arranged at one end of a two-armed lever 74 swingably arranged about pivot 76. A similar lever 77 is rotatable about a pivot 78 rigidly connected to the I-bearn 37. The two levers 74 and 77 are mechanically coupled by means of a rod 79. The lever 77 con be rotated about pivot 78 by means of a pull rod 81 provided with a handle 82.

It will be seen that the lever 77 can act on the lever 70 only in the extreme position of the carriage carrying the flat sections 46 which function as supports for the movable supporting bars 54. Projections 73 and 80 are stops for the levers 70 and 74, respectively, and projections 62 and 64 are stops for the pawls and 61, respectively, in their upper positions (Fig. 3), while pro jections 63 and are stops for the said pawls 60 and 61, respectively, in their lower positions (Fig. 4). The purpose of the restoring levers 83 and 84 is described more in detail hereinafter.

The carriage is pushed by the .edges of the sheets, which contact vertical strips 154 rigidly fixed in the moving carriage. bars 5051 are recessed in order to accommodate these strips.

Alternatively (see Fig. 6), instead of vertical strips 154 for the carriage, a push rod 17a secured to beam 37 by strap 17b and roller 17c may be coupled with the driving system of the push rods 17 so that it engages I-beam 41 of the carriage to move the same and the associated section 46 with the movable row of supporting bars 50 mounted thereon during the forward stroke of the push rods 17 to the left. 0n the return stroke of such a rod, however, the carriage will not be taken wheels 87.

' Let it be assumed thatxthe transporting plates 2b together with pressed, but practically not yet cooled sheets 1b are on the tables 7 of the unloading frame 6. In

.the stacking frame, the pawls 60 and 61 are in upper locking position (Fig. 3) so that the supporting bars 50 and 51 are horizontally arranged. Furthermore, the

-. carriage with the left row of supporting bars 50 shall be assumed to ;be in" the extperne right position adjacent As shown in Fig. 3a, the supporting 6 the right row of bars 51. This position of bat-s50 is shown in dotted lines in Fig. 3. H I I The push rods 17 are now simultaneously driven and, with their shoes 19, push the plates 1b out ofthe unloading frame 6 without, however, influencing the transporting plates 2b which at this point remain on their respective tables 7. The sheets 1b thus glide over the rollers 31 and slide over the supporting bars 51. As soon as the sheets 1b are pushed forward so far that the forward edge portions thereof are sufliciently advanced beyond the supporting bars 50 to engage vertical strips 154 mounted on the carriage, the latter will be pushed from the position shown in dotted lines in Fig. 3 through the full line position and up to the dot-dash line position shown in the same figure. In the event that a pushing rod is utilized as previously described, when the end of the same reaches the I-beam 41 of the carriage and pushes it, the wheels 39 and 40 thereon roll on the I- beams 37 with the speed of the pushing rods 17. After reaching the final position shown in dot-dash lines, the push rods 17 (and the additional pushing rod when employed) are withdrawn simultaneously. The plates 44 of the carriage, in this position, are nearly in contact with emergency stops 43 (one of which is visible in the drawings) when the board edges are used to push the carriage and may be used as movement limiting contact stops when a push rod for the carriage is used.

The twelve sheets 1c are each now supported along two parallel side edges, after a transport carriage 85 has been placed underneath the stacking fname, the releasing handle 82 may be operated, thus elfecting a lifting of the rollers 71 and 75. The pawls 60 and 61 are now rotated downward-1y on their respective pivots 57 and 59 by means of the weight of the rods 52. and 53 and the supported sheets 10. As the lowering of the rods 52 and 53 occurs, all the supporting bars 50 and 51 are rotated toward the vertical position (Fig. 4) and the sheets 10 held by them lose their support and drop to form a stack on the table 86 of the transport carriage 85. The bars 50 and 51, together with the vertical strips 154 formsmooth, effectively sealed walls, which guide the dropping sheets, and prevent the air in between the same from escaping too soon, so braking the fall. In order to avoid the setting up of stresses in the uppermost sheet 1, the same may be covered by a cover plate 86a of metal, wood or a sheet similar to those in the underlying stack. Then the entire stack is conveyed into the cooling compartment where it is turned on end, placed into position and cooled for a longer period of time without occupying much room.

The operational stages described hereinbefore follow each other at short intervals. Thus it is impossible that the sheets be cooled unsymmetrically before the formation @of the stack or that they attain unequal amounts of moisture at the two surfaces thereof as referred to hereinbefore.

The restoring of the supporting members 50 and 51 to sheet supporting position is elfected in \a simple way by hand 'by means of the levers 83 and 84 which are pivotably mounted on the lowermost pivots and 151, respectively, and are provided with notches 183 and 184, respectively. As indicated by the dotted line arrows on Fig. 4, the levers 83 and 84 may be swung inwardly so that their respective notches 183 and 184 engage the lowermost pivots 152 and 153 mounted inrods 52 and 53 to thereby lift the aforesaid pivots and with it their respective rods 52 and 53. In this manner, all the arms 54 and 55 are pivoted on their respective pivots 150 and 151 and with them supporting bars 50 and 51 to the reset position shown in Fig. 3. Levers 83 and 84may be manipulated even though a previous stack is still positioned beneath the device on carriage 85 since they rotate in planes outside that of the edges of the boards seen'in Fig.4.. t

Alternatively, as disclosed in Fig. 6 two pneumatic cylinders 201 may be used to return the rods 52 and 5,3 to the upward position. These cylinders maybe fixed on the vertical members 46 and '47 with the piston rods 202 pointing downwards so as to engage and actuate levers 54a and 55a similarly to levers 83 and 84.

The piston rods, not being connected to the levers '83- and 84 return by spring force 263, and so do not interferev with a quick movement of the rods 52 and 53.

If desired, electrical or preferably electro-pneumatic means may 'be provided for automatically effecting the release of rods 52 and 53 when the pressed sheets are shifted into" the stacking frame 35 and lie on the supporting bars 50 and 51. These eleetro-pneunratic means may comprise a cylinder 204 which is fixed on top of the beam 37 and arranged to actuate connecting rod 79. The supply to the cylinder can be effected by a solenoid 20S and valve 206, actuated by a push-button whether or not it be used in conjunction with a limit switch 207 tripped by the plate 44 in the left end position shown in Figs. 3 and 6. Thus, a locking mechanism is provided. Alternatively, in certain cases it may be adisable to provide locking means adjustable by hand which make it impossible to actuate the handle 82 in the blocking condition of the locking means even in the left hand position of the carriage as viewed in Fig. 3.

Having now described the invention so that others skilled in the art may clearly understand the same, What I claim is:

1. A process .fOr stacking a plurality of hot sheets previously pressed on a plurality of transporting plates in a multiple press comprising the steps of simultaneously separating the hot sheets from the transporting plates, positioning and supporting the sheets one above the other in spaced relationship to each other at two opposite edges of each sheet, removing such edge support from all the ,sheets simultaneously While they are still hot so that they drop fireely upon one another and thus form a stack, and then covering the uppermost sheet so that an unsymmetrical radiation of heat or a unilateral transfer of moisture to the ambient *air cannot take place in any sheet of the stack.

2. A process for stacking a plunality of hot sheets previously pressed on a plurality of transporting plates in a multiple press comprising the steps of moving the transporting plates with the hot sheets thereon out of the press in one direction to a first station, moving the hot sheets off the transporting plates in another direction perpendicular to the first direction to a. second station, supporting the sheets one above the other in spaced relationship to each other at tW opposite edges of each sheet at said second station, and then removing such edge support from all the sheets simultaneously so that they drop freely upon one another and thus form a stack at said second station.

3. A process for stacking a plurality of hot sheets previously pressed on a plurality of transporting plates in a multiple press comprising the steps of pulling the transporting plates with the hot sheets thereon out of the press in one direction to a first station, pushing the hot sheets off the transporting plates in another direction perpendicular to the first direction to a second station, support ing the sheets one above the other in spaced relationship to each other at two opposite edges of each sheet at said second station, and then removing such edge support from all the sheets simultaneously so that they drop freely upon one another and thus form a stack at said second station. n

4. An apparatus for handling sheets pressed in a mult-iple press on transporting plates comprising means for removing the transporting plates with the pressed sheets thereon from the press, means for removing the sheets from he transporting plates to a device for stacking the sheets, said device comprising a frame, a plurality-of movable sheet edge supporting members mounted in pairs on said frame, one pair above the other in spacedi'ela tionship to. adjacent pairs, said members of each pair be? i-ng arranged at substantially the same'level, and means for moving all said movable members simultaneously from sheet edge supporting position to non-supporting position whereby the sheets moved to and supported on said members will drop freely upon one another and form a stack.

5. An apparatus for handling sheets pressed in a multiple press on transporting plat-es comprising means for removing the transporting plates with the pressed sheets thereon from the press, means for pulling the transporting plates with the pressed sheets thereon from the press in one direction, means for pushing the sheets from the transporting plates in a direction perpendicular to said one direction to a device for stacking the sheets, said device comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair above the other in spaced relationship to adjacent pairs, said members of each pair being arranged at substantially the same level, and means for moving all said movable members simultaneously from sheet edge supporting posit-ion to non-supporting position whereby the sheets moved to and supported on said members will drop freely upon one another and form a stack.

6. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair above the other in spaced relationship to adjacent pairs, said members of each pair being arranged at substantially the same level, and means for moving all said movable members simultaneously from sheet edge supporting position to non-supporting position whereby the sheets supported on said members will drop freely upon one another and form a stack.

7. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair being above the other and in spaced relationship to adjacent pairs, said members of each pair being arranged at substantially the same level, means for locking all said pairs of members in sheet edge supporting position against the force of gravity, and means for releasing said locking means to permit moving of all said movable members simultaneously from sheet edge supporting position to non-supporting position by the force of gravity whereby the sheets supported on said members will drop freely upon one another and form a stack.

8. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members pivotably mounted in pairs on said frame, one pair being above the other and in spaced relationship to adjacent pairs, said members of each pair being arranged at substantially the same level; means for looking all said pairs of members in sheet edge supporting position against the force of gravity, said locking means comprising a first connecting rod mechanically linked to one supporting member of each pair and a second connecting rod mechanically linked to the other supporting member of each pair, and holding means for each said connecting rod; and means for releasing said holding means to permit moving of both said rods and with them pivoting of all said movable members simultaneously from sheet edge supporting position to non-supporting position by the force of gravity whereby the sheets supported on said members will drop freely upon one another and form a stack.

9. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair being above the other and in spaced relationship to adjacent pairs to form two vertical rows of supporting members, said members of each pair being arranged at substantially the same level, one of said rows being supported on a carriage movably mounted on said frame for movement thereon towards and away from the other of said rows of supporting members, and means for moving all said movable members simultaneously from sheet edge supporting position to non-supporting position whereby the sheets supported on said members will drop freely upon one another and form a stack. 1

10. A device for stacking a plurality of sheets comprising a frame, a plurality of movable'sheet edge supporting members mounted in pairs on said frame, one pair being above the other and in spaced relationship to adjacent pairs to form two vertical rows of supporting members, said members of each pair being arranged at substantially the same level, one of said rows being supported on a carriage movably mounted on said frame for movement thereon towards and away from the other row, means for pushing sheets onto said pairs of supporting members, means for pushing said carriage with said one row of supporting member away from said other row with the same speed that said sheet pushing means operates, and means for moving all said movable members simultaneously from sheet edge Supporting position to nonsupporting position whereby the sheets supported on said members will drop freely upon one another and form a stack.

11. A device for stacking -a plurality of sheets comprising :a frame, a plurality of movable sheet edgesup'porting members mounted in pairs on said frame, one pair being above the other and in spaced relationship to adjacent pairs to form two vertical rows of supporting members, said members of each pair being arranged at substantially the same level, one of said rows being supported on a carriage movably mounted on said frame for movement thereon towards and away from the other row, means for locking all said pairs of members in sheet edge supporting position against the force of gravity, and means for releasing said locking means to permit moving of all said movable members simultaneously from sheet edge supporting position to non-supporting position by the force of gravity whereby the sheets supported on said members will drop freely upon one another and form a stack, said releasing means being operable with regard to said locking means for said one row only when said carria-ge and said one row supported thereon is moved a predetermined distance from said other row.

12. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair being above the other and in spaced relationship to adjacent pairs, said members of each pair being aranged at substantially the same level, means for locking all said pairs of members in sheet edge supporting position against the force of gravity, means for releasing said locking means to permit moving of all said movable members simultaneously from sheet edge supporting position to non-supporting position by the force of gravity whereby the sheets supported on said members will drop freely upon one another and form a stack, and means for returning said movable members to said sheet edge supporting position.

13. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair being above the other in spaced relationship to adjacent pairs to form two vertical rows of supporting members, said members of each pair being arranged at substantially the same level, one of said rows being supported on a carriage movably mounted on said frame for movement thereon towards and away from the other row, and means for locking all said pairs of members in sheets edge supporting position against the force of gravity; said means comprising a plurality of swinging arms each connected at one end thereof to one of said movable supporting members for movement therewith, said swinging arms of each row of supporting members being connected at the other ends thereof to one of two linking members, each linking member being common to one of said rows of supporting members, means supporting each said linkingmember on said frame and comprisa ing a pawl pivoted at one end thereof and mounted on said frame and having the operative engaging surface thereof located at the other end, each said linking member being pivotally connected to its respective supporting pawl at a location between said ends thereof, a separate pawl engaging member movably mounted on said frame for movement toward and away from engagement with the operative engaging surface of each of said pawls, and actuating means for moving said pawl engaging members simultaneously out of engagement with their respective pawls to permit moving of both said linking members and all said movable members simultaneouslyfrom sheet edge supporting position to non-supporting position by the force of gravity whereby the sheets supported on said members will drop freely upon one another and form a stack.

14. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair being above the other in spaced relationship to adjacent pairs to form two vertical rows of supporting members, said members of each pair being arranged at substantially the same level, one of said rows being supported on a carriage movably mounted on said frame for movement thereon towards and away from the other row, and means for looking all said pairs of members in sheet edge supporting position against the force of gravity; said means comprising a plurality of swinging arms each connected at one end thereof to one of said movable supporting members for movement therewith, said swinging arms of each row of supporting members being connected at the other ends thereof to one of two linking members, each. linking member being common to one of said rows of supporting members, means supporting each said linking member on said frame and comprising a pawl pivoted at one end thereof and mounted on said frame and having the operative engaging surface thereof located at the other end, each said linking member being pivotally connected to its respective supporting pawl at a location between said ends thereof, a separate pawl engaging member movably mounted on said frame for movement toward and away from engagement with the operative engaging surface of each of said pawls, and actuating means for moving said pawl engaging members simultaneously out of engagement with their respective pawls to permit moving of both said linking members and all said movable members simultaneously from sheet edge supporting position to non-supporting position by the force of gravity whereby the sheets supported on said members will drop freely upon one another and form a stack, said actuating means being operable with regard to disengaging said pawl for said one row only when said carriage and said one row supported thereon is moved a predetermined distance from said other row.

15. A device for stacking a plurality of sheets as defined in claim 14 in which the separate pawl engaging member cooperating with the pawl with which said one row is operatively associated is mounted on said carriage.

16. A device for stacking a plurality of sheets as defined in claim 15 in which the actuating means comprises a rod which is linked to the pawl engaging member operatively associated with the pawl of said other row and has means connected thereto which are operable to engage the pawl engaging member mounted on said carriage only when the carriage is at a predetermined location on the frame.

17. A process for stacking a plurality of sheets comprising the steps of positioning and supporting the sheets one above the other in spaced relationship to each other at two opposite edges of each sheet and then pivoting such edge support from all the sheets simultaneously while substantially air sealing the area occupied by the sheets in the region of said opposite edges thereof by forming a vertical wall of said edge supports so that said sheets drop 11 n ra ed an e upon one, n thsr an h i a stack.

18. A process for stacking a plurality of sheets comprising the steps of supporting the sheets one above the other in spaced relationship to each other at two opposite edges of each sheet, pivoting such edge support from all the sheets simultaneously, and immediately upon such removal substantially air sealing the area occupied by the sheets in the region of said opposite edges thereof by forming a vertical wall of said edge supports and guiding the edges of the sheets so that the latter drop in a braked manner upon one another and thus form a stack.

19. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair above the other in spaced relationship to adjacent pairs, said members of each pair being arranged at substantially the same level, each said member having at least one surface of substantially greater area than the thickness of the sheets to be stacked, and means for moving all said movable members simultaneously from sheet edge supporting position to a non-supporting position wherein said surface areas of each pair are directed in a vertical direction to close off and provide substantial air seals in the regions of said supporting members whereby the sheets supported on said members will drop in a braked manner upon one another and form a stack.

20. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said frame, one pair above the other in spaced relationship to adjacent pairs, said members of each pair being arranged at substantially the same level, each said member having one surface of substantially greater area than the thickness of the sheets to be stacked, and means for moving all said movable members simultaneously from sheet edge supporting position to a non-supporting position wherein said surface areas of each of the two vertically aligned groups of members present a substantially closed continuous sealing and guiding wall whereby the sheets supported on said members will drop in a braked and guided manner upon one another and form a stack.

21. A device for stacking a plurality of sheets comprising a frame, a plurality of movable sheet edge supporting members mounted in pairs on said; frame, one pair bei g ab ve t e. other and in spaced nship to adjacent pairs to form two vertical rows of supporting members, said members of each pair being arranged at substantially the same level, one of said rows being supported on a carriage movably mounted on said frame for movement thereon towards and away from the other row, means for pushing sheets onto said pairs of supporting members, abutment means mounted on said carriage, said abutment means being positioned to be engageable by the leading edges of the sheets being pushed onto said supporting members on said carriage whereby said carriage is pushed away from said other row with the same speed that said sheet pushing means operates, and means for moving all said movable members simultaneously from sheet edge supporting position to non-supporting position whereby the sheets supported on said members will drop freely upon one another and form a stack.

22. A process for stacking a plurality of hot sheets previously pressed on a plurality of transporting plates in a multiple press comprising the steps of simultaneously separating the hot sheets from the transporting plates,

positioning and supporting the sheets one above the other in spaced relationship to each other at two opposite edges of each sheet, and removing such edge support from all the sheets simultaneously while they are still hot so that they drop freely upon one another and thus form a stack.

References Cited in the file of this patent UNITED STATES PATENTS 1,148,244 Macnaughtan July 27, 1915 1,262,335 Hansalpakar Apr. 9, 1918 1,319,391 Harvey Oct. 21, 1919 1,473,395 Luce Nov. 6', 1923 1,688,219 Williams Oct. 16, 1928 1,766,251 Greenleaf June 24, 1930 2,019,732 Mandusic Aug. 6, 1935 2,072,667 Coe Mar. 2, 1937 2,612,275 Chapman Sept. 30, 1952 2,636,625 Pries Apr. 28, 1 953 2,728,468 Siempelkamp Dec. 27, 1955 FOREIGN PATENTS 54,805 Norway Jan. 14, 1935 

